New images, taken with the 520-megapixel Dark Energy Camera (DECam) on the Víctor M. Blanco 4-m Telescope at the Cerro Tololo Inter-American Observatory, represent a portion of the second data release from the Survey of the MAgellanic Stellar History (SMASH), the deepest, most extensive survey of the Magellanic Clouds (high-resolution images: the Large Magellanic Cloud and the Small Magellanic Cloud).
Part of the SMASH dataset showing an unprecedented wide-angle view of the Large Magellanic Cloud. Image credit: CTIO / NOIRLab / NSF / AURA / SMASH / D. Nidever, Montana State University / Travis Rector, University of Alaska Anchorage / Mahdi Zamani & Davide de Martin.
The Large and Small Magellanic Clouds are located 160,000 and 200,000 light-years from Earth, and stretch 15,000 and 7,000 light-years across, respectively.
They are the largest satellite galaxies of the Milky Way and, unlike the rest of the satellite galaxies, are still actively forming stars — and at a rapid pace.
Though large numbers of dwarf galaxies such as the Magellanic Clouds populate the Universe, the vast majority are too faint and distant for astronomers to study.
Having the Large and Small Magellanic Clouds as neighbors provides astronomers with a unique opportunity to investigate the formation and evolution of small galaxies.
“These satellite galaxies have been studied for decades, but SMASH is being used to map out their structure over their full, enormous extent and help solve the mystery of their formation,” said Montana State University’s Dr. David Nidever, principal investigator of the SMASH survey.
“To date, this is the deepest and most extensive astronomical dataset of the Magellanic Clouds, which are the closest large galaxies to us.”
The complete SMASH survey covers an area 2,400 times greater than the full Moon, and required about 50 nights of specialized observations.
The second data release contains new data from DECam on the central and most complex regions of the Magellanic Clouds.
Part of the SMASH dataset showing what is arguably the best wide-angle view of the Small Magellanic Cloud to date. Image credit: CTIO / NOIRLab / NSF / AURA / SMASH / D. Nidever, Montana State University / Travis Rector, University of Alaska Anchorage / Mahdi Zamani & Davide de Martin.
Dr. Nidever and colleagues are using their deep dataset to study the history of star formation across both of these dwarf galaxies.
They have uncovered evidence that the pair have collided with each other in the recent past and that this sparked the recent episode of intense star formation.
“These are beautiful multicolor images of the Milky Way’s nearest neighboring galaxies,” said Dr. Glen Langston, program officer of National Science Foundation.
“Through the care the dedicated team has taken, they give us a remarkable view of the 13 billion year history of star formation in these galaxies.”
One of the astronomers’ long-term goals is to use the information they have obtained about the history of star formation to create a ‘movie’ of how the Magellanic Clouds evolved over time.
“These latest SMASH data of the central regions of the Magellanic Clouds, where most of the stars are found, are unique in their combined depth, breadth, and uniformity,” said SMASH survey co-leader Dr. Knut Olsen, an astronomer at NSF’s National Optical-Infrared Astronomy Research Laborator (NOIRLab).
“Besides producing amazing images, these data allow us to look into the past and reconstruct how the Magellanic Clouds formed their stars over time; with these ‘movies’ of star formation we can try to understand how and why these galaxies evolved.”
The second data release of the SMASH survey is described in a paper to be published in the Astronomical Journal.
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David L. Nidever et al. 2020. The Second Data Release of the Survey of the MAgellanic Stellar History (SMASH). ApJ, in press; arXiv: 2011.13943
